WO2003099571A1

WO2003099571A1 - Ink remaining amount measuring device, ink-jet recorder comprising same, ink remaining amount measuring method, and ink cartridge

Info

Publication number: WO2003099571A1
Application number: PCT/JP2003/006794
Authority: WO
Inventors: Yuichi Nishihara
Original assignee: Seiko Epson Corporation
Priority date: 2002-05-29
Filing date: 2003-05-29
Publication date: 2003-12-04
Also published as: CN1326703C; US7325892B2; EP1508450A1; CN1655940A; US20050212836A1; JP2004050824A; EP1508450A4

Abstract

An ink remaining amount measuring device for an ink-jet recorder having high ink measuring accuracy and high reliability by accurately measuring the residual vibration due to resonance between a vibration element and a medium such as ink in contact with the vibration element without being influenced by noise. The ink remaining amount measuring device comprises a piezoelectric element (12) provided in an ink tank (11), an excitation pulse generating section (13) for applying an excitation pulse to the piezoelectric element (12), a sensor section (14) for measuring the frequency of the counter-electromotive force waveform from the piezoelectric element (12) caused by the residual vibration due to resonance with the medium in the ink tank (11), and a judging unit (15) for judging from the measured frequency whether or not any ink is present. The sensor section (14) has two band-pass filters (22A, 22B) for passing only the waveforms in predetermined frequency bands predetermined depending on the presence/absence of the ink and a frequency measuring section (150) for counting the binarized counter-electromotive force waveforms, measuring the time between a pulse of a predetermined ordinary number and a pulse of another predetermined ordinary number after the first pulse, and measuring the frequencies of the counter-electromotive force waveforms with reference to the time.

Description

Description Ink remaining amount detecting device, ink jet recording device and ink remaining amount detecting method using the same, and ink cartridge

- Technical field

The present invention relates to a device and method for detecting the remaining amount of ink in an ink jet recording apparatus, and more particularly to a technique for detecting a change in acoustic impedance to detect the remaining amount of ink in an ink tank of an ink jet recording apparatus. Background art

In general, an ink jet recording apparatus includes a carriage equipped with an ink jet recording head having pressure generating means for pressurizing a pressure generating chamber and a nozzle opening for discharging the pressurized ink as ink droplets. An ink tank that stores ink supplied to the recording head via a path, and is configured to be capable of continuous printing.

Here, the ink tank is generally configured as a cartridge that is removable from the recording apparatus so that the user can easily replace the ink tank when the ink is consumed.

By the way, as a method of managing the ink consumption of the conventional ink cartridge, the number of ink droplets ejected by the recording head and the amount of ink sucked in the maintenance process of the printing head are integrated by software, Manage ink consumption by calculating ink consumption in a calculation or by attaching two electrodes for liquid level detection directly to the ink cartridge to detect when a predetermined amount of ink is actually consumed. Methods and the like are known.

However, the method of managing the consumption of ink by calculation by integrating the number of ink droplets ejected and the amount of sucked ink by software depends on the usage environment, for example, the temperature and humidity in the usage room, the opening of the ink cartridge, etc. The pressure in the ink cartridge and the viscosity of the ink may vary depending on the elapsed time afterwards, the frequency of use on the user side, etc. This causes a problem that a non-negligible error occurs between the calculated ink consumption and the actual consumption. Another problem is that even if the ink amount per dot varies due to individual differences of the ink jet head, an error occurs between the calculated ink consumption and the actual consumption. Furthermore, if the same cartridge is once removed and re-installed, the accumulated count value is reset once, so that there is a problem that the actual remaining ink amount cannot be determined.

On the other hand, the method of managing the point at which ink is consumed by the electrode can detect the actual amount of ink consumption at one point, so that the remaining amount of ink can be managed with high reliability. However, in order to detect the liquid level of the ink, the ink needs to be conductive, so that the kind of ink that can be used is limited. There is also a problem that the liquid-tight structure between the electrode and the ink cartridge is complicated. Furthermore, since a noble metal having good conductivity and high corrosion resistance is usually used as a material of the electrode, there is a problem that the manufacturing cost of the ink cartridge is increased. In addition, the two electrodes must be mounted at different locations on the ink cartridge, which complicates the manufacturing process and increases the manufacturing cost.

On the other hand, there has been proposed an ink remaining amount detecting device which detects the presence or absence of an ink based on a residual vibration frequency of a vibration element such as a piezoelectric element. That is, when a vibration element such as a piezoelectric element and a medium (ink, air, etc.) in contact with the vibration element are in a resonance state, the residual vibration frequency of the vibration element such as a piezoelectric element is the vibration element such as a piezoelectric element. And the resonance frequency between the medium and the medium in contact with the medium. The above-described ink remaining amount detection device detects the state of the ink serving as the medium based on the change in the resonance frequency.

By the way, from the viewpoint of power saving, there is an increasing tendency to set a low drive voltage in various electronic devices and the like, and a demand for a lower drive voltage in an ink jet printer is also increasing. .

In the above-described ink remaining amount detection device, the above-described residual vibration frequency is conventionally obtained by pulse driving a piezoelectric element with a driving voltage of, for example, 5 V. ing.

However, if the driving voltage of the piezoelectric element is set to, for example, 3.3 V with a reduction in the driving voltage, the vibration applied to the piezoelectric element becomes smaller due to the lowering of the voltage. Therefore, the level of the detection signal due to the residual vibration decreases.

Therefore, when the presence or absence of ink in the ink tank is detected based on the detection signal of the residual vibration, the level of the detection signal decreases. For example, noise or head drive by motors of an ink jet recording apparatus is performed. It is susceptible to noise due to waveform induction. As described above, the ink remaining amount detection device that detects the presence or absence of ink based on the residual vibration frequency of the vibrating element is sensitive to noise, and in a noisy environment, the detection accuracy is reduced, and in some cases, the detection is performed. There is a problem that it becomes difficult.

In addition, in such an ink remaining amount detecting device, when the position of the liquid surface of ink or the like is at a position substantially equal to a vibration element such as a piezoelectric element functioning as a sensing element (a boundary area between the presence or absence of ink), the movement of the carriage or the like is prevented. If the ink surface foams or undulates, there is a risk of erroneously detecting the presence or absence of ink.

Therefore, an object of the present invention is to apply excitation to a vibrating element such as a piezoelectric element and to reliably detect residual vibration due to resonance with a medium such as ink in contact with the vibrating element without being affected by noise or the like. Another object of the present invention is to provide a technique for detecting the remaining ink amount of an ink jet recording apparatus, which is adapted to enhance the ink detection accuracy and reliability.

Another object of the present invention is to provide excitation to a vibrating element such as a piezoelectric element so that residual vibration due to resonance with a medium such as ink that is in contact with the vibrating element is reduced by the movement of a carriage or the like. An object of the present invention is to provide a technique for detecting the remaining ink amount of an ink jet recording apparatus capable of preventing erroneous detection even when bubbling or waving of the liquid surface occurs. Disclosure of the invention

In order to solve the above-mentioned problem, the present invention includes at least one filter means for passing only a waveform in a predetermined frequency band assumed in advance with or without ink with respect to a back electromotive force waveform from a vibrating element. Provided, the reverse passed through this filter means By detecting the frequency of the electromotive force waveform, the presence / absence of an ink is reliably determined without being affected by noise or the like.

That is, in the ink remaining amount detecting device of the present invention, the vibration element provided in the ink tank, the excitation pulse generation unit for applying an excitation pulse to the vibration element, and the residual vibration due to the resonance of the medium in the ink tank A detection unit for detecting the frequency of the back electromotive force waveform from the vibrating element based on the frequency, and a determination unit for determining the presence or absence of ink based on the frequency detected by the detection unit. The detection unit includes at least one filter unit that passes only a waveform in a predetermined frequency band assumed in advance with or without ink, and binarizes a back electromotive force waveform from the vibrating element. Frequency detection means for measuring the time between a predetermined number of pulses from a predetermined number and detecting the frequency of the back electromotive force waveform based on this time. To.

According to this configuration, the frequency of the back electromotive force waveform from the vibration element based on the residual vibration due to resonance with the medium in the ink tank can be detected without transmitting noise by at least one filter means. The presence or absence of ink can be reliably determined.

Further, in the ink remaining amount detection device of the present invention, the filter means includes an ink-equipped band-pass filter and an ink-equipped band-pass filter that pass only a waveform in a predetermined frequency band assumed in advance with or without an ink. And a band-pass filter for absent, and wherein the frequency detecting means detects a frequency of a back electromotive force waveform passing through the band-pass filter for the presence of the ink or the band-pass filter for the absence of the ink.

According to this configuration, the back electromotive force that passes through the band pass filter for the presence of an ink or the band pass filter for the absence of the ink that passes only the waveform in the predetermined frequency band assumed in advance with or without ink, respectively. Since the frequency can be detected only for the power waveform, it is possible to reliably determine whether or not there is an ink without being affected by noise or the like.

Further, in the ink remaining amount detecting device according to the present invention, the frequency detecting means has an ink for detecting a frequency of a waveform that has passed through the band pass filter for ink presence. And a frequency counter for detecting no ink for detecting a frequency of a waveform passed through the bandpass filter for no ink. According to this configuration, two measurement circuits provided in parallel, ie, a band-pass filter for ink and a frequency counter for ink, and a band-pass filter for ink-free and a frequency counter for ink-free, simultaneously remain in two measurement circuits. The frequency of the back electromotive force waveform from the vibrating element based on vibration can be detected.

Further, in the ink remaining amount detecting device of the present invention, the band pass filter for the presence of ink and the band pass filter for the absence of ink may have a resonance frequency of the vibrating element when each center frequency is with or without ink. And each pass band is set to a size that allows individual variation of the vibrating element.

According to this configuration, the present invention can be applied to an ink jet recording apparatus while allowing individual variations of sensors.

Further, in the ink remaining amount detecting device according to the present invention, a dead band is provided between both pass bands of the band pass filter for ink and the band pass filter for no ink.

According to this configuration, even when the position of the liquid surface of the ink or the like is substantially equal to the position of the vibrating element (boundary region of the presence or absence of the ink), the liquid surface of the ink or the like due to the movement of the carriage or the like is caused by the bubbling or waving It is possible to prevent erroneous detection of the presence or absence of the ink to be used.

Further, in the ink cartridge of the present invention, an ink cartridge containing ink used for printing is mounted on an ink jet recording apparatus, and a vibration element provided in the ink cartridge; An excitation pulse generating section for applying a voltage, a detecting section for detecting a frequency of a back electromotive force waveform from the vibrating element based on residual vibration due to resonance with a medium in the ink cartridge, and A determination unit for determining the presence or absence of an ink,

The detection unit includes at least one filter unit that passes only a waveform in a predetermined frequency band assumed in advance with or without ink, and binarizes a back electromotive force waveform from the vibrating element and powers it. Frequency detecting means for measuring a time between a predetermined number of pulses from a predetermined number and detecting a frequency of the back electromotive force waveform based on the time. It is characterized by having.

According to this configuration, the frequency of the back electromotive force waveform from the vibration element based on the residual vibration due to resonance with the medium in the ink cartridge can be detected without transmitting noise by at least one filter. The presence or absence of ink can be determined at a time.

In the ink remaining amount detecting method for an ink jet recording apparatus according to the present invention, an excitation pulse is applied to a vibration element provided in the ink tank, and the vibration element based on residual vibration due to resonance with a medium in the ink tank is applied. A method for detecting the frequency of the back electromotive force waveform from the device, and determining the presence or absence of ink based on the detected frequency, wherein the remaining amount of ink in the ink tank used in the ink jet recording apparatus is detected. With respect to the back electromotive force waveform, only the waveform of a predetermined frequency band supposed in advance with or without ink is passed by the filter means, and the passed waveform is binarized and counted. , A time between a predetermined number of pulses is measured, and the frequency of the back electromotive force waveform is detected based on this time.

According to this configuration, the frequency of the back electromotive force waveform from the vibrating element based on the residual vibration due to the resonance with the medium in the ink tank can be detected without transmitting the noise by the filter means. Can be determined. Further, in the ink remaining amount detecting method of the ink jet recording apparatus according to the present invention, the ink remaining amount is detected by counting the number of dots of ink ejected from a print head in the ink jet recording apparatus. It is characterized by using a detection method together.

According to this configuration, it is possible to detect an ink end more accurately than when only the method of detecting the remaining amount of ink by counting the number of dots of ink is used. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram showing a configuration of an ink remaining amount detecting device according to the first embodiment of the present invention.

FIG. 2 is a wiring diagram illustrating a specific configuration example of an amplification unit of a detection unit in the remaining ink amount detection device of FIG. FIG. 3 is a flowchart illustrating the operation of detecting the remaining amount of ink in the ink remaining amount detecting device of FIG.

FIG. 4 is a time chart showing signals of various parts in the frequency measurement of the residual vibration in FIG.

FIG. 5 is a flowchart showing the details of the operation of the residual vibration frequency measurement (steps A3 and A7 in the flowchart shown in FIG. 3) in the ink remaining amount detecting device in FIG.

FIG. 6 is a block diagram showing a configuration of an ink remaining amount detecting device according to the second embodiment of the present invention.

FIG. 7 is a flowchart showing the operation of detecting the remaining amount of ink in the remaining ink amount detecting device of FIG.

FIG. 8 is a diagram for explaining a method for detecting the remaining amount of ink according to the third embodiment of the present invention.

FIG. 9 is a flowchart showing the operation of detecting the remaining amount of ink in the third embodiment of the present invention.

FIG. 10 is an external perspective view of an ink cartridge according to the fourth embodiment of the present invention.

FIG. 11 is a cross-sectional view of a sensor unit provided on a side of the ink cartridge shown in FIG.

FIG. 12 is a functional block diagram of an ink remaining amount detection circuit and the like of an ink cartridge according to a fourth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail through embodiments of the present invention. The following embodiments do not limit the claimed invention, and not all combinations of the features described in the embodiments are necessarily essential to the solution of the present invention. An ink remaining amount detection device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a first embodiment of an ink remaining amount detecting device according to the present invention. In FIG. 1, an ink remaining amount detecting device 10 includes a piezoelectric element 12 as a vibrating element provided in a cartridge type ink tank 11 which is detachable from an ink jet recording apparatus (an ink jet printer). An excitation pulse generator 13 for applying an excitation pulse to the piezoelectric element 12, and detecting a frequency of a back electromotive force waveform based on residual vibration due to resonance of ink generated in the piezoelectric element 12. A detection unit 14, a determination unit 15 for determining the presence or absence of ink, and a control unit 200 for controlling the excitation pulse generation unit 13, the detection unit 14, and the determination unit 15 are configured. . Here, the piezoelectric element 12 in FIG. 1 is actually provided for each ink tank 11 for each color in a print head unit of an ink jet printer.

The piezoelectric element 12 is, for example, a piezo element. The piezoelectric element 12 is displaced by an applied voltage, and resonates with a medium, that is, ink or air in the ink tank 11, to generate residual vibration due to the resonance. It is configured as follows. Note that a back electromotive force waveform is generated in the piezoelectric element 12 due to the residual vibration.

The excitation pulse generator 13 has two types of excitation pulses registered in advance, and is configured to select and output these excitation pulses.

Here, of the two types of excitation pulses, the first type of excitation pulse is an excitation pulse having a pulse width and a period corresponding to residual vibration due to resonance with ink when ink is present in ink tank 11. The second excitation pulse is an excitation pulse having a pulse width and a period corresponding to residual vibration due to resonance with air when there is no ink in the ink tank 11.

In the case shown in the figure, the detection section 14 is composed of an amplification section 16, a band pass filter (BPF) 22 A for ink, a band pass filter (BPF) 22 B for inkless, and a frequency measurement section 150. It is composed of The frequency measuring section 150 further has a pulse counting section 170 and a pulse width measuring section 180.

For example, as shown in FIG. 2, the amplifying unit 16 amplifies the back electromotive force waveform from the piezoelectric element 12 by an operational amplifier 16a, and forms the waveform with the reference voltage V ref as the center of vibration. Is configured. The above-mentioned band pass filter for ink presence (BPF) 22A and the band pass filter for ink absence (BPF) 22B can be obtained by the ink remaining amount detection device of the present embodiment when ink has or does not have the center frequency. This is a bandpass filter (bandpass filter) that matches the frequency of the output waveform. In other words, the band pass filter (BPF) 22A with ink has its center frequency adjusted to 100 kHz, which is the frequency of the output waveform when ink is present. On the other hand, the band pass filter (BPF) 22B for no ink has its center frequency adjusted to 160 kHz, which is the frequency of the output waveform when there is no ink.

The band pass filter (BPF) 22A for ink and the band pass filter (BPF) 22B for no ink each have a pass band width of ± 10 kHz of the center frequency. This takes into account individual variations of the piezoelectric element 12 as a sensor. That is, the band pass filter for ink presence (BPF) 22 A has a pass bandwidth of 90 kHz to 110 kHz. On the other hand, the inkless bandpass filter (BPF) 22B has a pass bandwidth of 150 kHz to 170 kHz. Therefore, the frequency range between 110 kHz and 150 kHz, which is an intermediate frequency band between the pass bands of both filters, is a B-band so that it becomes a kind of dead band as a sensor.

The first feature of this embodiment is that two bandpass filters (band-pass filters) are used in accordance with the frequency of the output waveform when ink has the center frequency and when there is no ink, respectively. It is in.

The second characteristic point is that the pass bandwidths of both filters are set so that the individual frequency fluctuations of the sensors are taken into account and the frequency range between the pass bandwidths of both filters is the dead band described above. On the point.

The frequency measuring section 150 is a frequency counter provided for the two filters, the band pass filter for ink presence (BPF) 22 A and the band pass filter for ink absence (BPF) 22 B, only one. The connection can be switched between the band pass filter (BPF) 22A for ink and the band pass filter (BPF) 22B for no ink by the control signal from 200. The pulse counting unit 170 in the frequency measuring unit 150 is supplied from the amplifying unit 16 via a band-pass filter (BPF) 22 A for ink or a band-pass filter (BPF) 22 B for ink-free. The input back electromotive force waveform is compared with a reference voltage V ref by a comparator, and when the back electromotive force waveform is higher than the reference voltage V ref, a signal is output to be binarized. It counts the pulses of the back electromotive force waveform and generates a time measurement pulse that goes to the H level only for the time between a predetermined number of pulses and a predetermined number of pulses (for example, the fifth to eighth pulses). The pulse width measuring section 180 measures the pulse width of the time measurement pulse from the pulse counting section 170, calculates the number of pulses per unit time, and calculates the frequency of the pulse of the back electromotive force waveform. Is detected.

The determination unit 15 determines whether or not there is an ink at a height position where the piezoelectric element 12 is provided in the ink tank 11 based on the frequency of the pulse of the back electromotive force waveform detected by the detection unit 14. The determination is performed, and the determination result is output to, for example, a control unit 200 provided in a printer body of the ink jet printer.

The control unit 200 includes, for example, a microcomputer, a CPU, and the like, and controls the excitation pulse generation unit 13, the detection unit 14, and the determination unit 15 in accordance with the ink remaining amount detection method according to the present invention. Thus, the remaining amount of ink is detected as described later.

Note that the control unit 200 may be configured so that the main control unit of the printer body has the function.

The ink remaining amount detecting device 10 according to the first embodiment of the present invention is configured as described above, and is based on the ink remaining amount detecting method according to the first embodiment of the present invention and according to the flowchart of FIG. It operates as follows.

First, in step A1, after the control unit 200 clears the re-measurement flag, in step A2, the control unit 200 sends a control signal to connect the frequency measurement unit 150. To the band pass filter (BPF) 22 A for ink. In step A3, the excitation pulse generating section 13 selects a target frequency, that is, an excitation pulse when there is an ink as an excitation pulse, and generates this excitation pulse. As a result, the piezoelectric element 12 becomes By applying the excitation pulse shown in Fig. 4 (A) Vibrate. The ink in the ink tank 11 resonates due to the vibration of the piezoelectric element 12, so that the piezoelectric element 12 generates residual vibration due to the resonance. Then, the control unit 200 controls the detection unit 14 to measure the frequency of the residual vibration of the piezoelectric element 12 as described below.

That is, the piezoelectric element 12 generates a back electromotive force waveform as shown in FIG. 4 (B) due to residual vibration caused by resonance with the ink in the ink tank 11.

This back electromotive force waveform is amplified around the reference voltage Vref by the operational amplifier 16a of the amplifier 16 as shown in FIG. When the ink level is higher than the position of the sensor in the ink tank 11, that is, the position where the piezoelectric element 12 is located (when ink is present), the back electromotive force waveform is 9 OKHz or higher due to variations in the solid state of the sensor. It has a frequency between 1 1 OKH z. Therefore, since the frequency is within the passband of the bandpass filter for ink (BPF) 22A, it passes through the bandpass filter for ink (BPF) 22A and is input to the pulse number measurement unit 170 of the frequency measurement unit 150. Is done. Then, the pulse number counting section 170 binarizes this back electromotive force waveform by comparing it with a reference voltage V ref by a comparator, as shown in FIG. 4 (D), and counts this binarized signal. Then, as shown in Fig. 4 (E), a time measurement pulse that is at the H level is generated only for the time between a predetermined pulse and a predetermined pulse (fifth to eighth pulse in the illustrated case).

As a result, the pulse width measuring unit 180 measures the pulse width of the time measurement pulse, and obtains the residual vibration frequency from the pulse width. At this time, even if high-frequency noise or the like due to the induction of the motor or head drive waveform of the ink jet printer is applied to the sensor system from the piezoelectric element 12, such high-frequency noise or the like has the frequency that ink is present. Since the band pass filter (BPF) is not within the pass band of 22 A, it cannot pass through the band pass filter for ink (BPF) 22 A, and therefore, the pulse counting unit 1 of the frequency measuring unit 150 Then, in step A4, the control unit 200 checks the generation of the time measurement pulse within a predetermined time, for example, to generate the piezoelectric element 12 by resonance with the ink. It is determined whether the frequency measurement of the residual vibration was successful or not. Then, the frequency is output, and the determination section 15 determines the presence or absence of ink, and terminates the operation of detecting the remaining amount of ink.

Here, the determination unit 15 determines the presence or absence of ink by determining whether or not the residual vibration frequency is within the frequency range when ink is present.

If the residual vibration frequency does not correspond to the case where ink is present, processing may be performed in the same manner as in the case where measurement failed in step A4.

On the other hand, if the residual vibration frequency measurement fails in step A4, the control unit 200 sends a control signal to connect the frequency measurement unit 150 in step A6. To the bandpass filter for inkless (BPF) 22B. Then, in step A7, the target frequency, that is, the second excitation pulse when there is no ink as the excitation pulse for the piezoelectric element 12 is selected, and this second excitation pulse is generated. As a result, the piezoelectric element 12 vibrates and resonates with the ink or air in the ink tank 11. The piezoelectric element 12 generates residual vibration due to resonance with ink or air. Then, the control unit 200 controls the detection unit 14 as described later, and measures the frequency of the residual vibration of the piezoelectric element 12.

Subsequently, in step A8, the control unit 200 determines whether or not the frequency measurement of the residual vibration was successful. If the measurement was successful, the control unit 200 similarly outputs the frequency in step A5. Then, the determination unit 15 determines that there is no ink, and ends the operation of the remaining ink amount detection.

If the residual vibration frequency does not fall within the frequency range when there is no ink, the processing may be performed in the same manner as in the case of the measurement failure in step A8.

If the re-measurement flag is not set in step A9, the control unit 200 sets the re-measurement flag in step A10, and then sets the ink jet in step A11. The carriage motor and the paper feed motor for moving the printer head of the portable printer are stopped, and the process returns to step A2 after the ink discharge is stopped. As a result, the influence of noise and the like due to the drive waveform signal at the time of noise ejection by the carriage motor and the paper feed motor is eliminated, and the ink remaining amount is detected again.

On the other hand, if the re-measurement flag is set in step A 9 above, Since the remaining amount of ink is measured again from step A10 to step A8 after step A11 and step A8, the control unit 200 sets the ink remaining amount at step A12. As the amount detection failure, appropriate processing such as stopping the printing operation of the ink jet printer is performed, and the operation of the remaining ink amount detection is ended. In the above-described embodiment, the excitation pulse generating unit 13 has registered in advance two types of excitation pulses corresponding to the residual vibration of the piezoelectric element 12 when ink is present and when ink is not present. The frequency of the residual vibration is measured by the first excitation pulse when there is ink, and when the measurement fails, the frequency of the residual vibration is measured by the second excitation pulse when there is no ink.

In this case, the measurement of the residual vibration frequency (the contents of steps A3 and A7 in FIG. 3) by the ink remaining amount detecting device 10 is performed as follows according to the flowchart shown in FIG.

That is, if the target frequency is set to “ink present” in step A 2 of the flowchart of FIG. 3 described above, first, in step B 1 of FIG. 5, the control unit 200 first executes the excitation pulse generation unit in step B 1. According to 13, the number of pulses (P n) of the first excitation pulse as the target pulse is set to one (P n = l). In step B2, the excitation pulse generator 13 generates one first excitation pulse (a pulse corresponding to the presence of ink), and applies the excitation pulse to the piezoelectric element 12. Then, in step B3, the control unit 200 controls the detection unit 14 to amplify the back electromotive force pulse based on the residual vibration due to the resonance with the ink generated in the piezoelectric element 12 by the amplification unit 16 The signal is amplified by the operational amplifier 16a of the above, and in step B4, is compared with the reference voltage Vref by the comparator 16b to be binarized.

Subsequently, in step B5, the control unit 200 counts the binary signal by the pulse number counting unit 170, and outputs a predetermined number of pulses from a predetermined number (for example, 5th to 8th). The pulse width of the time measurement pulse is measured by the pulse width measurement unit 180, and the frequency of the residual vibration of the piezoelectric element 12 is calculated. Measure.

Then, in step B6, the control unit 200 determines whether the pulse width has been measured within a predetermined time, that is, whether the time measurement has timed out. If (Yes in step B6), it is determined in step B7 whether n has reached the maximum value. If n has not reached the maximum value, the pulse is determined in step B8. Increase the number by one (n = n + l), and return to step B2 to measure again. This is repeated. In Step B7, if the detection is not possible even if the number of pulses is increased until n reaches the maximum value (Pn = Pnmax) (Yes in Step B7), then in Step B9 Then, the ink remaining amount detection (measurement) fails, and the process proceeds from step A4 to A6 in the flowchart of FIG. 3 described above. That is, a second excitation pulse (a pulse adjusted for no ink) is set as a target pulse.

On the other hand, if the timeout has not occurred in step B6, the control unit 200 determines in step B10 whether or not the frequency of the residual vibration is within the frequency range when ink is present. If the frequency of the residual vibration is within the frequency of the presence of ink, it is determined in step B11 that there is ink, and the ink remaining amount detection (measurement) is successful. Proceed from step A4 to A5.

If the frequency of the residual vibration is not within the frequency with ink at step B10, it is determined at step B12 whether the frequency of the residual vibration is within the frequency range without ink. If the frequency of the residual vibration is within the frequency of no ink, it is determined in step B13 that there is no ink. Similarly, the ink remaining amount detection (measurement) is successful, and the flow chart of FIG. Proceed from step A4 to A5. On the other hand, if the frequency of the residual vibration is not within the frequency of no ink in step B12, it is not possible to determine the presence or absence of ink, so the process proceeds to step B7 and performs the same processing as the timeout. . That is, the measurement is repeated while increasing the number of pulses up to PnmaX. In addition, the operation of step A7 in FIG. 3 (when the process proceeds to A7 force and A8) also follows the flowchart in FIG. 5 in the same manner as above.

In this way, by measuring the residual vibration frequency of the piezoelectric element 12 due to resonance with the ink in the ink tank 11 using a plurality of excitation pulses, it is possible to determine whether a more accurate ink exists. A determination can be made.

Now, as in the present embodiment, even in the case of an ink remaining amount detection device that uses the residual vibration frequency of the vibrating element, as described above, the position of the liquid surface of ink or the like is reduced as described above.

"Position approximately equal to vibration element such as piezoelectric element that functions as element (with ink If there is bubbling or waving of the liquid surface of the ink etc. due to the movement of the carriage, etc., when there is an error, there is a risk of erroneously detecting the presence or absence of the ink.

However, in the ink remaining amount detecting device of the present embodiment, the pass band width of the band pass filter for ink presence (BPF) 22 A and the pass band width of the band pass filter for ink absence (BPF) 22 B Since the frequency range of 110 kHz to 150 kHz is set to be a kind of dead band as a sensor, the position of the ink level in the ink tank 11 is piezoelectric. When at a position substantially equal to the element 12 (a boundary area with or without ink), the dead band of the output caused by the bubbling of the ink liquid surface caused by the movement of the carriage or the like is cut off by this dead band, The erroneous detection described above is not performed. That is, in this case, the measurement fails in any of the residual vibration frequency measurements in steps A3 and A7 in the flowchart of FIG. 3, and eventually, the process proceeds to step A11, where the printer head of the ink jet printer is used. The carriage motor and the paper feed motor for moving the carriage stop, and further wait until the ink discharge stops, and return to step A2, and the drive waveform signal at the time of the noise ejection by the carriage motor and the paper feed motor. This completely eliminates the effects of noise and the like caused by, and performs the remaining ink level detection again.

As described above, the ink remaining amount detection device of the present embodiment can prevent erroneous detection even when the ink level rises or undulates due to the movement of the carriage or the like. In addition, in any of the residual vibration frequency measurements in steps A3 and A7 in the flowchart of FIG. 3, as described above, high-frequency noise and the like caused by the induction of the motor and head drive waveforms of the ink jet printer are generated from the piezoelectric element 12. Even if it is applied to the sensor system of the above, such a high frequency noise, etc., is within the pass band width of the band pass filter (BPF) 22 A for ink and the band pass filter (BPF) 22 B for ink. Therefore, it cannot pass through the band pass filter (BPF) 22A for ink or the band pass filter (BPF) 22 B without ink, and therefore, the pulse number counting section of the frequency measuring section 150 It is not input to 170. Therefore, it is possible to accurately detect the presence / absence of ink and the like without the influence of such noise.

In addition, in the ink remaining amount detecting device of the present embodiment, motors such as a carriage motor, Since the influence of noise due to the ink discharge drive waveform signal can be eliminated, the printing operation of the ink jet printer is not stopped, that is, the carriage motor and the paper feed motor are stopped. Even without stopping, there is an effect that it is possible to detect the presence or absence of ink relatively accurately. For this reason, detection is possible even while the carriage is moving (main scanning), but the detection timing is as follows: a series of carriages that print from the stop position at a constant speed after accelerating, and then decelerate to a stop. It is preferable to perform the detection during printing at a constant speed in the movement operation of the edge. This is because bubbling and waving of the liquid surface of the ink and the like due to the movement of the carriage described above are relatively small.

FIG. 6 shows a configuration of a second embodiment of the ink remaining amount detecting device according to the present invention. The basic configuration of the ink remaining amount detecting device of the present embodiment is substantially the same as that of the first embodiment described above. Hereinafter, the same portions are denoted by the same reference numerals, and the description thereof will be described. Omitted. In FIG. 6, the detection unit 14 ′ includes an amplification unit 16, a band-pass filter (BPF) 22 A for ink, a frequency measurement unit 15 OA connected to a band-pass filter (BPF) 22 A for ink, and no ink. It consists of a band-pass filter (BPF) 22B and a frequency measuring unit 15 OB connected to the ink-free band-pass filter (BPF) 22B. The frequency measuring unit 15 OA further has a pulse counting unit 170 A and a pulse width measuring unit 180 A, and the frequency measuring unit 150 B further has a pulse counting unit 170 B and a pulse width measuring unit. Has 180 B. As described above, in the present embodiment, the band pass filter (BPF) 22A for ink and the frequency measurement unit 15 OA connected thereto, the band pass filter (BPF) 22B for ink free and the frequency connected thereto It has two frequency measuring circuits, measuring unit 150B, and measures the pulse frequency when there is ink and the pulse frequency when there is no ink with each circuit. The ink remaining amount detecting device 10 ′ according to the second embodiment of the present invention is configured as described above, and is based on the ink remaining amount detecting method according to the second embodiment of the present invention. Operates as follows.

First, after the control unit 200 clears the re-measurement flag in Step C1, in Steps C2A and C2B, the band pass filter (BPF) for ink 22 A Residual vibration of the piezoelectric elements 1 and 2 in the BPF circuit for ink and the band measurement filter (BPF) 22B and the BPF circuit for inkless and consisting of 22B and the frequency measurement unit 150B. At the same time. That is, in step C2A, the excitation pulse generating section 13 selects a target frequency, that is, an excitation pulse when there is ink as an excitation pulse, and generates this excitation pulse. As a result, the frequency of the residual vibration of the piezoelectric element 12 is measured as shown in FIGS. In step C 2 B, the excitation pulse is generated by the excitation pulse generator 13 by selecting an excitation pulse when there is no ink as a target frequency, that is, an excitation pulse. Thereby, the frequency of the residual vibration of the piezoelectric element 12 is measured as shown in FIGS. 4 (A) to 4 (E).

At this time, even if high-frequency noise or the like due to induction of a motor or head drive waveform of an ink-jet printer is applied to the sensor system from the piezoelectric element 12, such a high-frequency noise or the like has the frequency that ink is present. Bandpass filter (BPF) 22 The bandpass filter for ink (BPF) is not within the pass band of 2 A, and is not within the passband of bandpass filter for inkless (BPF) 22B. ) 22 A or no ink bandpass filter (BPF) cannot pass through 22 B, so that noisy noise does not affect the frequency measurement of residual vibration.

Subsequently, in step C3, the control unit 200 measures the frequency of the residual vibration of the piezoelectric element 12 in the ink-containing BPF circuit by, for example, confirming the generation of the time measurement pulse within a predetermined time. It is determined whether or not the printing has succeeded. If the printing has succeeded, the frequency is output in step C4, the determination section 15 determines that there is ink, and ends the operation of detecting the remaining amount of ink. Here, the determination unit 15 determines the presence or absence of ink by determining whether the residual vibration frequency is within the frequency range when there is an ink. '

On the other hand, if the measurement of the frequency of the residual vibration fails in step C3, in step C5, the control unit 200 similarly confirms the generation of the time measurement pulse within a predetermined time. It is determined whether or not the frequency measurement of the residual vibration of the piezoelectric elements 1 and 2 has been successful in the ink-free BPF circuit. Then, the frequency is output, the determination unit 15 determines that there is no ink, and ends the operation of detecting the remaining amount of ink. Here, the determination unit 15 determines that there is no ink by determining whether the residual vibration frequency is within the frequency range when there is no ink. On the other hand, if the residual vibration frequency measurement fails in step C5 above, it is determined in step C6 whether the re-measurement flag is set and the re-measurement flag is set. If not, the control unit 200 sets the re-measurement flag in step C7, and then in step C8, controls the carriage motor and paper feed for moving the head of the ink jet printer to the printer. Wait until the motor stops and the ink discharge stops, then return to steps C2A and C2B. This eliminates the influence of the noise caused by the carriage motor and the paper feed motor and the noise due to the drive waveform signal at the time of ink ejection, and again detects the remaining ink amount.

On the other hand, if the re-measurement flag is set in step C6 above, steps C2A and C2B go to step C5 through steps C7 to C8. In step C9, the control unit 200 determines that the remaining amount of the ink has failed, and for example, stops the printing operation of the ink jet printer. : Process is completed, and the operation for detecting the remaining ink amount ends. ^ By operating as described above, the remaining ink amount detection device 10 'of the present embodiment provides the same operational effects as those of the above-described first embodiment.

FIG. 8 is a block diagram showing an overall configuration of a printer 300 according to the third embodiment of the present invention. The illustrated printer 300 includes a printer controller 310 and a print engine 320. The printer controller 310 temporarily stores an interface (hereinafter, referred to as “host I / F”) 311 that receives print data from the host computer 400 and print data input to the printer 300. Input buffer 312 A, output buffer 312 A interprets print data stored in input buffer 312 A and develops it as image data for printing (image) A ROM 313 storing routines, etc., a CPU 314, a print control circuit for sending head data and the like to the printer (print) head 322 side, a semiconductor contributing circuit for a specific application including various motor drivers, etc. A pp 1 ied S em iconductor Integrated A print control AS IC 315 consisting of Circuit (hereinafter referred to as “AS IC”) and an interface (hereinafter “mechanical I / F”) for transmitting image data and drive signals to the print engine 320レ,) and 316. Host I / F 311, input buffer 312 A, output (image) buffer 312 B, ROM 313, CPU314, print control AS IC 315, mechanical I / F 316, bus 31 7 Are connected to each other.

The host IZF 311 includes a FIFO buffer or the like that temporarily stores data for transmission to and reception from the host computer 400, and receives print commands or data from the host computer 400. The input buffer 312A temporarily stores print data and the like received by the FIFO buffer in the host 1 F311. In the output (image) buffer 312B, for example, image data in raster graphics format after the analysis of the print command or data is developed. The ROM 313 stores various control programs executed by the CPU 314 and the like. The ROM 313 also stores font data (not shown), graphic functions, various procedures, and the like. The CPU 314 plays a central role in various controls in the printer of the present embodiment.

The print engine 320 includes a print head 322, a carriage mechanism 324, and a paper feed mechanism 326. The paper feed mechanism 326 includes a paper feed motor, a paper feed roller, and the like, and sequentially feeds a print storage medium such as a recording paper to perform a sub-scan. The carriage mechanism 324 includes a carriage on which the print head 322 is mounted, a carriage motor for running the carriage via a timing belt, and the like, and causes the print head 322 to perform main scanning. The ink cartridge constituting the ink tank 11 'of this embodiment is set by being fitted into the housing of the carriage. The print head 322 has, in the sub-scanning direction, an ink jet nozzle array for each color composed of, for example, 96 nozzles, and ejects ink droplets from each nozzle at a predetermined timing.

Graphics data captured by the host computer 400 via an image scanner or the like (not shown) is converted into data (control commands and print data) that can be interpreted by the printer 300 by a printer driver on the host computer 400. Is replaced. The converted data is transmitted from the interface (I / F) of the host computer 400 via the connection cable 415 while being managed by the operating system (OS) on the host computer 400. In the printer 300, the host I / F 311 receives the control command and print data, and the CPU 314 interprets the control command and print data. The image data is expanded into print image data by the printer 312B and printed by the print engine 320. The status of the printer, such as the printer status, including the remaining amount of ink, is managed in real time by a status confirmation unit (not shown) of the printer 300, and is transmitted via a data transmission unit (not shown) in the host IZF 311. The remaining amount of ink is displayed on a monitor screen (not shown), for example, by the printer driver on the host computer 400.

The feature of this embodiment is that the method for detecting the remaining ink amount by the ink remaining amount detecting device (ink level sensor) 10 or 10 according to the first or second embodiment described above is a method for calculating the remaining ink amount by software ( Soft count). The software program related to the ink remaining amount calculation method includes a control program stored in the ROM 313 executed by the CPU 314 and the like. According to the present embodiment, as a method of calculating the amount of remaining ink by software, the number of ink dots ejected from the printer (printing) head 3 22 is counted, and this is multiplied by the amount of ink per dot. Obtain the consumed ink amount, subtract this consumed ink amount from the total amount of unused ink, and calculate the ink amount used for maintenance of head cleaning such as ink suction (bombing). Use the method to calculate the remaining ink.

The formula for calculating the remaining ink amount by this soft count is expressed by the following formula (1).

I (remain) = I (full)-(Count * dl)-I (maintain) · 'Formula (1) Ϊ,

I (r amain): Remaining amount of ink

I (full): Ink amount when ink cartridge is not used Count: Dot count number

dl: Ink amount per dot

I (maintain): The amount of ink used for maintenance such as head cleaning.

Here, dl varies depending on the individual difference of the head and the state of the ink, but is calculated with the maximum dl that can be assumed in order to prevent the blank hit due to the ink break.

Therefore, according to the ink remaining amount calculation method using this software, an error is gradually accumulated between the calculated ink remaining amount and the actual ink remaining amount as the ink is consumed. Therefore, as shown in FIG. 8, for example, although the ink is consumed only from the bottom of the ink tank (ink cartridge) 11 1 ′ to the position (ink level) 81 at a certain height, the dot It is also conceivable that the ink end is counted. In other words, the portion from the bottom of the ink tank 11 ′ shown in FIG. 8 to the ink level position 81 (indicated by the arrow 82) is calculated by the software using the ink cartridge. This is a calculation error included in the minute, and must be allowed as a margin to prevent empty printing due to running out of ink.

Therefore, in this embodiment, by using the ink remaining amount detection method according to the first or second embodiment described above together with the ink remaining amount calculation method by the software, the ink is used up to the end, in other words, It enables more accurate ink end detection.

That is, in this embodiment, the piezoelectric element 12 as a sensing element in the ink remaining amount detection device (ink level sensor) 10 or 10 ′ according to the above-described first or second embodiment is shown in FIG. As described above, the ink tank 11 1 ′ is provided at a position higher than the ink liquid level position 81, which is a limit of the soft count. For more accurate ink end detection, it is desirable to provide the ink level higher than the ink liquid level 81 and near the bottom of the ink tank 11 '. If a sufficient amount of ink is contained in the ink tank (ink cartridge) or 11 ', the ink is detected by the ink level sensor (ink level sensor) 10 or 10' including the piezoelectric element 12 It is determined that there is. Therefore, the detection of the remaining amount of ink by the ink remaining amount detection device (ink level sensor) 10 or 10 ′ is continued, and the boundary area of the presence or absence of ink (for the first time, (At the time when the piezoelectric element 12 is fixed), the remaining ink amount can be accurately determined from the position at which the piezoelectric element 12 is fixed. Eliminate the problem, perform dot counting again from here, and consume ink until the ink runs out. In the area indicated by the arrow 83 in FIG. 8 as well, the calculation of the ink remaining amount by the software includes an error. Since the accumulated error in the area is corrected, the ink can be used up to the ink liquid level position 84, and the ink remaining in the ink cartridge (ink tank 1 1 ') at the time of ink end can be reduced. Can be done.

As shown in FIG. 8, the piezoelectric element 12 is provided at a position higher than the ink liquid level position 81 which is a limit by the soft count. Therefore, if the ink remaining is detected by software calculation of the ink remaining amount even though the ink remaining amount detecting device (ink level sensor) 10 or 10 'determines that there is ink, the remaining ink is detected. It is considered that some trouble has occurred in the ink amount sensor (ink level sensor). To prevent idling due to lack of ink, use ink end at that point. Hereinafter, the method for detecting the remaining amount of ink according to the present embodiment will be described with reference to the flowchart in FIG.

First, in step D1, the ink cartridge (ink tank 111) is started to be used, and in step D2, as the printing operation is performed, the ink is consumed and the ink cartridge (ink tank 111 ′) is consumed. The ink inside is decreasing. In step D3, the remaining ink amount is calculated by the above-described soft count. At a predetermined timing in step D4, the remaining ink amount is detected by the ink remaining amount detecting device (ink level sensor) 10 or 10 '. Then, it is determined whether or not the ink remaining amount detecting device (ink level sensor) 10 or 10 ′ has detected the absence of ink (step D 5). If the absence of ink is detected (step D 5) Y es), and corrects the ink remaining amount calculation formula based on the soft count described above (step D6).

That is, assuming that the amount of ink (arrow 83) from the position of the piezoelectric element 12 of the ink remaining amount detector (ink level sensor) 10 or 10 'to the bottom of the ink tank 11' is I (few), When the sensor detects no ink, I (remain) = I (few)

I (ful l) = I (few)

Count = 0

I (maintain) = 0

By setting, the accumulated calculation error up to that point can be made zero, and the ink remaining amount is calculated using the soft count again. You can reduce the remaining amount.

Further, at the time when the ink remaining amount detecting device (ink level sensor) 10 or 10 ′ detects the absence of ink, the above dl is corrected from the difference between the calculated remaining ink amount and the actual ink remaining amount. Can be. By using the corrected dl to calculate the remaining amount of ink below the piezoelectric element 12 of the ink remaining amount detector (ink level sensor) 10 or 10 ', more accurate ink end determination can be performed. It is possible to further reduce the remaining amount of ink. If the amount of ink per dot differs depending on the print mode, each dot is counted for each ejection mode, and the remaining ink amount is calculated using the ratio of the amount of ink in each mode. After correcting the formula for calculating the remaining amount of ink as described above (step D6), the printing operation is continued in step D7. As a result, the ink is further consumed, and the ink in the ink cartridge (ink tank 11 ′) is reduced. In step D8, the remaining ink amount is calculated by the above-described soft count. Then, it is determined whether or not the ink remaining amount by the soft count has become 0 (step D9). If the ink remaining amount has become 0 (Yes in step D9), it is determined that the ink is out ( Step D 10) As described above, the printer driver on the host computer 400 shown in FIG. 8 notifies the user by displaying the ink end on a monitor screen (not shown) or the like (step D 10). In step Dl 1), the operation of detecting the remaining amount of ink is ended. On the other hand, if no ink is detected in step D 5 (No in step D 5), the remaining amount of ink by the soft count is 0. Judge power If the value is 0 (Yes in step D12), it is determined that the ink cartridge (ink tank 1 1 ') is abnormal (step D13), and an ink cartridge error is displayed on the monitor screen. Is displayed to the user (step D14), and the operation for detecting the remaining amount of ink ends. On the other hand, if it is not 0 (No in step D12), the process returns to step D2 to continue the printing operation.

As described above, according to the ink remaining amount detecting method of the present embodiment, the ink remaining amount calculating method using software and the ink remaining amount detecting method according to the above-described first or second embodiment are used together. Using up the ink to the end, in other words, more accurate detection of the incend becomes possible.

In the above-described embodiment, a piezoelectric element such as a piezo element is used as the vibrating element. However, the present invention is not limited to this. For example, another piezoelectric element such as an electrostrictive element or a magnetostrictive element, or another vibrating element. May be used.

In the above-described embodiment, only one ink tank 11 is illustrated. However, the present invention is not limited to this. In an ink jet printer that performs color printing of four to seven colors, etc. A vibrating element is provided for each ink tank, and the frequency of the back electromotive force waveform based on the residual vibration caused by resonance with the medium such as ink is detected for each vibrating element to detect the remaining amount of the ink. On the other hand, in the above-described embodiment, an example in which only one ink remaining amount detection device 10 is provided in the ink tank 11 has been described. (Depth) A plurality of ink remaining amount detectors are installed at different positions, and the excitation pulse applied to each ink remaining amount detector is measured while switching between the ink presence and the Z absence. Good. This makes it possible to measure not only the presence / absence of ink but also the remaining ink level.

Also, in the above-described embodiment, two types of excitation pulses, an excitation pulse for ink and an excitation pulse for no ink, are registered in advance, but inks having different physical properties, such as different viscosities, are used. Assuming a case, it is possible to register a plurality of types of excitation pulses in advance.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. You. The ink remaining amount detecting device of the present invention can be provided in an ink cartridge detachably mounted on an ink jet printer, and the present embodiment shows such an example.

FIG. 10 is an external perspective view of an ink cartridge 100 provided with the remaining ink amount detection device of the present embodiment. The ink cartridge 100 is internally used as a consumable

A housing 140 that accommodates one type of ink is provided. An ink supply port 110 for supplying ink to a printer described later is provided at a lower portion of the housing 140.

. At the top of the housing 140, a loop antenna for communicating with the printer by radio waves

There is provided a logic circuit 130 constituted by 130 and a dedicated IC chip. A sensor SS used for measuring the remaining amount of ink is provided on the side of the casing 140. The sensor S S is electrically connected to the logic circuit 130.

Figure 11 shows the sensor installed on the side of the housing 140 of the ink cartridge 100.

It is sectional drawing which shows the cross section of SS. The sensor SS includes the above-described piezoelectric element 12, two electrodes 1 10, 11 1 for applying a voltage to the piezoelectric element 12, and a sensor attachment 112. The electrodes 110 and 111 are connected to the logic circuit 130. The sensor attachment 112 is a structural part of the sensor SS having a thin film that transmits vibration from the piezoelectric element 12 to the ink and the housing 140.

FIG. 11A shows a case where the ink remains at a predetermined amount or more and the ink level is higher than the position of the sensor SS (FIG. 10). FIG. 11 (b) shows a case where the ink does not remain more than a predetermined amount and the ink level is lower than the position of the sensor SS. As can be seen from these figures, when the ink level is higher than the position of the sensor SS, the sensor SS, the ink, and the housing 140 are vibrators, but the ink level is the position of the sensor SS. If it is lower, only a small amount of ink adhering to the sensor SS, the housing 140 and the sensor SS becomes a vibrator. As a result, the vibration characteristics around the piezoelectric element 12 change according to the remaining amount of ink. Also in the present embodiment, the measurement of the remaining amount of ink is performed using such a change in the vibration characteristic. The details of the measurement method are the same as in the first and second embodiments described above, and a description thereof will be omitted.

Fig. 12 is composed of a dedicated IC chip provided in the ink cartridge 100. FIG. 2 is a block diagram centered on a logic circuit 130 to be implemented. The logic circuit 130 includes an excitation pulse generator 13 for applying an excitation pulse to the piezoelectric element 12 and the piezoelectric element 12 as in the first and second embodiments. A detecting unit 14 for detecting the frequency of the back electromotive force waveform based on the residual vibration due to the resonance with the generated ink, a determining unit 15 for determining the presence or absence of ink, and an excitation pulse generating unit 13 for these. An RF conversion unit 202 is provided in addition to a control unit 200 that controls the unit 14 and the determination unit 15.

The RF converter 202 includes a demodulator (not shown) that demodulates radio waves received from the printer 302 via the loop antenna 120, and a modulator that modulates a signal received from the controller 200. And a modulator (not shown) for transmitting to the printer 302. The printer 302 uses the loop antenna 120 to transmit a baseband signal to the ink cartridge 100 using a carrier having a predetermined frequency. On the other hand, the ink cartridge 100 can change the impedance of the loop antenna 120 by changing the load of the loop antenna 120 without using a carrier. The ink cartridge 100 transmits a signal to the printer 302 using the fluctuation of the impedance. In this way, the ink cartridge 100 and the printer 302 can perform bidirectional communication.

The logic circuit 130 has, in addition to the above configuration, a power generation unit (not shown) that rectifies the carrier wave received by the RF conversion unit 202 and generates power at a predetermined voltage (for example, 5 V). It has. This power generation unit supplies power to the RF conversion unit 202, the control unit 200, and the like. It should be noted that a charge pump circuit for boosting a predetermined voltage generated by the power generation unit to a predetermined voltage required by the sensor SS and supplying power to the detection unit 14 may be provided.

As described above, in the present embodiment, not only the vibration element but also the excitation pulse generation unit, the detection unit, the determination unit, the filter unit, and the frequency detection unit are provided in the ink cartridge. Since the frequency of the back electromotive force waveform from the vibrating element based on the residual vibration due to resonance can be detected by the ink cartridge itself, it is possible to reliably determine the presence or absence of the ink.

Also, without being affected by individual differences between ink cartridges, for example, Even if the ink cartridge is replaced, accurate detection is possible.

In the present embodiment, the ink cartridge 100 and the printer 302 exchange information by wireless communication, and the printer main body moves along with the cartridge for printing. Therefore, there is no risk of contact failure or the like, and information can be exchanged stably.

As described above, according to the present invention, excitation is applied to a vibrating element such as a piezoelectric element, and residual vibration due to resonance with a medium such as ink in contact with the vibrating element can be reliably prevented without being affected by noise or the like. , And the accuracy and reliability of the ink detection can be improved. In addition, even when the carriage or the like moves to bubbling or waving of the liquid surface such as an ink, erroneous detection can be prevented.

In addition, by using this method together with the ink remaining amount calculation method by software, it is possible to detect ink more accurately.

The present invention can be realized in various modes. For example, the ink remaining amount detecting device and the detecting method described in the above embodiments, an ink jet printer, an ink cartridge used in the printer, and a printer In addition to the head, it can also be realized by a computer program for realizing the method or the function of the device, a recording medium recording the computer program, or the like.

Further, the present invention can be similarly applied to a facsimile, a copying machine, a plotter, and the like having a mechanism based on the same ink jet system as an ink jet recording apparatus. Industrial applications

INDUSTRIAL APPLICABILITY The present invention can be used to detect the ink consumption state (ink remaining amount) inside an ink container used in an ink jet recording apparatus.

Claims

The scope of the claims

1. A vibration element provided in the ink tank containing the ink, an excitation pulse generator for applying an excitation pulse to the vibration element, and a vibration element based on residual vibration caused by resonance with the medium in the ink tank. An ink remaining amount detection device for an ink tank, comprising: a detection unit that detects the frequency of the back electromotive force waveform of the above; and a determination unit that determines the presence or absence of ink based on the frequency detected by the detection unit.

The detection unit binarizes and counts a counter electromotive force waveform from the vibrating element, and at least one filter unit that passes only a waveform in a predetermined frequency band that is assumed in advance with or without an ink; And a frequency detecting means for measuring a time between a predetermined number of pulses from a predetermined number and a frequency of the back electromotive force waveform based on the time.

2. The filter means comprises an ink-containing band-pass filter and an ink-free band-pass filter that pass only a waveform in a predetermined frequency band that is assumed in advance with or without ink, respectively. 2. The ink remaining amount detecting device according to claim 1, wherein the frequency detecting means detects a frequency of a back electromotive force waveform that has passed through the band pass filter for having ink or the band pass filter for not having ink.

3. The frequency detecting means detects a frequency of the back electromotive force waveform passing through the band pass filter for ink, and a frequency counter for ink presence, and a back electromotive force passing through the band pass filter for no ink. 3. The ink remaining amount detecting device according to claim 2, further comprising: a frequency counter for detecting the frequency of the waveform.

4. The band pass filter for the presence of the ink and the band pass filter for the absence of the ink are adjusted to the resonance frequency of the vibrating element when each center frequency is provided with or without the ink. 4. The ink residual amount detecting device according to claim 2, wherein the size of the vibrating element is set to a value that allows individual variation of the vibrating element.

5. The band pass filter for the case with the ink and the band pass filter for the case without the ink The ink remaining amount detecting device according to any one of claims 2 to 4, wherein a dead zone is provided between both pass bands of the filter.

6. An ink jet recording apparatus, comprising: the ink remaining amount detecting device according to any one of claims 1 to 5.

7. An ink cartridge, which contains ink used for printing and is detachably mounted on the ink jet recording apparatus, and applies a vibration element provided in the ink cartridge and an excitation pulse to the vibration element. Excitation pulse generator, a detector that detects the frequency of the back electromotive force waveform from the vibrating element based on residual vibration due to resonance with the medium in the ink cartridge, and the presence or absence of ink based on the frequency detected by the detector And a determination unit for determining

The detection unit binarizes and counts the back electromotive force waveform from the vibrating element, and at least one filter unit that passes only a waveform in a predetermined frequency band assumed in advance with or without ink; Frequency detecting means for measuring a time between a predetermined number of pulses from a predetermined number and detecting a frequency of the back electromotive force waveform based on the time.

8. The filter means comprises an ink-containing band-pass filter and an ink-free band-pass filter that pass only a waveform in a predetermined frequency band that is assumed in advance with or without ink, respectively. 8. The ink cartridge according to claim 7, wherein the frequency detecting means detects a frequency of a back electromotive force waveform that has passed through the band pass filter for using ink or the band pass filter for using no ink.

9. The frequency detecting means detects the frequency of the back electromotive force waveform passed through the band pass filter for ink, and the frequency counter for ink presence, and the back electromotive force passed through the band pass filter for no ink. 9. The ink cartridge according to claim 8, further comprising: a frequency counter for inklessness that detects a frequency of the waveform.

10. The band pass filter for ink and the band pass filter for no ink are adjusted to the resonance frequency of the vibrating element when each center frequency is in the presence or absence of ink, respectively. Allow individual variation of the vibrating element 10. The ink cartridge according to claim 8, wherein the ink cartridge is set to an acceptable size.

11. The dead band is provided between the pass bands of both the band pass filter for ink and the band pass filter for ink absence, according to any one of claims 8 to 10, wherein The ink cartridge according to claim 1.

12. Further, an antenna for transmitting and receiving radio waves to and from the ink jet recording apparatus, and a signal received from the ink jet recording apparatus via the antenna is demodulated and input to the control unit, and received from the control unit. The ink cartridge according to any one of claims 8 to 11, further comprising: an RF conversion unit that modulates a signal and transmits the signal to the inkjet recording device via the antenna.

13. The cartridge according to claim 12, wherein the excitation pulse generation unit, the detection unit, the determination unit, the filter unit, the frequency detection unit, and the RF conversion unit are provided in a cartridge as a dedicated IC chip. 13. The ink cartridge according to any one of items 8 to 12.

14 4. Apply an excitation pulse to the vibrating element provided in the ink tank to detect and detect the frequency of the counter-electromotive force waveform from the vibrating element based on the residual vibration due to resonance with the medium in the ink tank. Determining the presence or absence of ink based on the detected frequency, the method for detecting the remaining amount of ink in an ink tank used in an ink jet recording apparatus. Only the waveform of the predetermined frequency band assumed according to the presence or absence is passed, the passed waveform is binarized and counted, and the time between a predetermined number of pulses from a predetermined number is measured, and this time is measured. And detecting the frequency of the back electromotive force waveform on the basis of the following.

15. A method for detecting the remaining amount of ink according to claim 14, wherein a method of detecting the remaining amount of ink by counting the number of dots of ink ejected from the print head in the ink jet recording apparatus is also used.